The overall objective of this proposal is to develop an improved tissue model for the study of human cytomegalovirus infection (CMV) during pregnancy. Specifically, rotating wall vessels (RWVs) will be utilized to establish this advanced model system. CMV is the leading cause of congenital viral infection, and intrauterine transmission of the virus occurs in approximately 50% of pregnant women with primary CMV infection. CMV infection during pregnancy can have catastrophic consequences not only on the neonate, but also on pregnancy outcome, including spontaneous abortion, intrauterine growth restriction and pre-eclampsia. Despite the significant morbidity and mortality associated with congenital CMV infection, little is known about how the virus infects the conceptus. RWV technology offers a unique approach not previously applied toward the study of placental tissues and provides a novel model system to explore intrauterine CMV infection. The culture conditions of these bioreactors provide a low-shear and low-turbulence growth environment, similar to that required for normal in vivo fetal and placental development. Such an environment allows cells to co-localize spatially, grow three-dimensionally, and differentiate into highly specialized tissues. Preliminary data presented in this proposal demonstrate that the RWV supports the growth of a first trimester cytotrophoblast cell line. Importantly, we have shown that the environment created within the bioreactor promotes cytotrophoblast differentiation and allows for the formation of complex, multi-layered three-dimensional (3-D) aggregates that are functionally similar to in utero trophoblast cells. The hypothesis to be tested within this proposal is that placental epithelial cells cultured in the RWV are functionally similar to the developing in utero placenta and that the 3-D growth of these cells will provide an improved model system for the study of the molecular details involved in intrauterine CMV infection. The long-term research goals of this proposal are to utilize the 3-D model to study and understand 1) the molecular details of normal placental development, 2) CMV pathogenesis, 3) host-pathogen interactions that occur at the maternal-fetal interface during pregnancy, and 4) the molecular mechanism(s) that regulate the effect of CMV on placentation and pregnancy outcome. The specific aims are: 1) to further characterize the 3-D model of human placentation, and 2) to apply the placental 3-D model toward the study of intrauterine CMV infection. This novel model system will contribute to advanced studies of human placentation, ultimately leading to new therapeutic strategies for the prevention and treatment of placental and congenital CMV infection.